Articulations are a toggle, but if you start with a selection where some notes are e.g. accented and others aren’t, clicking or typing the key command for accent once will add add accents to every note, and clicking or typing the key command for accent again will remove accents from every note.
It’s not a single keypress but it should be pretty quick to Select All and click each of the (lit) articulation icons in the left panel twice.